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Tony Spicer

Well Known Member
Two years ago when I was starting my RV-3, I wondered if it would be possible for it to be LSA compliant. So I asked EAA. Their response from November 2005 follows:

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"Since you are the builder of the aircraft you determine the gross weight, etc. and if operating as a sport pilot, you are responsible for flying only aircraft which qualify as an LSA.

The FAA preamble states:

"The FAA notes that compliance with light-sport aircraft parameters can be more readily verified for type-certificated aircraft than for amateur-built aircraft certificated under existing ?21.191 (g). Amateur-built aircraft do not have a TC, a flight manual, or a type certificate data sheet. Because of this, it may be difficult to determine if aircraft with other than a standard airworthiness certificate meet the limits listed for a light-sport aircraft and can be operated by a sport pilot. The FAA anticipates that the aircraft design consensus standard will include methodologies that will readily enable a determination that an aircraft design meets the light-sport aircraft definition."

The ASTM standards have addressed the FAA's preamble language. The ASTM standards clearly define what V sub H is in 3.2.32. The Committee felt and the FAA agreed that there was nothing more to say, fly the aircraft with maximum continues power in level flight record the speed and correct for standard day the answer is the answer nothing more needs to be defined.

The ASTM standard also includes 4.3.1 which states:
Maximum RPM shall not be exceeded with full throttle during takeoff, climb, or flight at 0.9 V H, and 110 % maximum continuous RPM shall not be exceeded during a glide at V NE with throttle closed.

So the above is one way to prove that your aircraft is an LSA which is acceptable to the FAA. Can you establish Vh some other way? I would say yes for an amateur built but I would definitely document it as part of my flight testing program.

Practical considerations are that the burden of proof will be on you to establish that an RV-3 meets the definition. A knowledgeable FAA Inspector who "knows" that an RV-3 doesn't fit LSA will violate you first and then let you prove that it is in compliance. If the FAA has nothing else to go on, they will no doubt revert to the engine manufacturer's documentation, which will have a specific maximum continuous power rating (which definitely won't be 55% power!). For example, Lycoming calls out a maximum continuous rated power and RPM for the O-320-A2B of 150 hp and 2700 rpm. It would be pretty tough to convince an FAA inspector that the Lycoming engine in your homebuilt (even if it's modified in some way) has a substantially different maximum continuous power rating than what's on the TC. Van's probably will give you no support since they do not view it as LSA eligible.

Also, I would guess that you could also run into some insurance problems as they will use readily available reference material to determine what they will insure for sport pilot operations."

Tony Spicer (just the messenger)
 
Few issues back in the RVator there was some notes from Van's aircraft for making RV-9(a) LSA. You better read it. And if I recall this has been discussed as well here in the forum some time ago -- not recently.

What comes to maximum continuous power -- I haven't seen that it would be restricted. Only maximum cruise speed has limit with full power. It ain't too hard to put limiter which limits your throttle like 75 % of maximum to meet this rules... or have a suitable propeller with proper pitch.
 
Geico266 said:
That is simply amazing, and the best chioce for LSA I can think of. I have heard there are now 3 RV9's flying as LSA.
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Actually... the amazing part, is that the rule to allow an aircraft to be licensed as E(xperimental)-LSA, requires that an S-LSA example has already been previously certified. Van's Aircraft (or anyone else) has never certificated an RV-9 as an S-LSA so these three RV-9's should never have received E-LSA certificates.
 
Not Quite Scott

Under 21.191(i)(1) until 1/31/2008, an aircraft may be be certified as E-LSA as an existing aircraft without such documentation. This rule covers the overweight, over seated, too fast ultralights. However, the applicant must show that the aircraft meets LSA parameters. And no one as yet has satisfactorily proven these parameters to me concerning any RV.
 
Mel said:
Under 21.191(i)(1) until 1/31/2008, an aircraft may be be certified as E-LSA as an existing aircraft without such documentation. This rule covers the overweight, over seated, too fast ultralights. However, the applicant must show that the aircraft meets LSA parameters. And no one as yet has satisfactorily proven these parameters to me concerning any RV.
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Of course your right Mel. I forgot that they can have been certified under the consenses standard with 21.191(i)(1) until Jan 31, 2008.

I do agree with your position...regardless of how the were certified, they probably should not have been.
 
RV-3 as LSA?

Greetings,

I've been trying to decide what to build next, and have been looking at sport pilot type designs. Unfortunately, I just don't find them all that interesting, mostly because they all seem about the same to me.

The more I think about it, the more I think the RV-3 could be made into a Sport Pilot compliant aircraft fairly easily. The speed is really the only problem, and that's easily limited. I just wondered if I was the only one who was thinking about this?

Cheers,
Rusty
 
Tony Spicer said:
Rusty,
Nope, you're not the only one that thought of doing that. But you must have missed this post:

http://www.vansairforce.com/community/showpost.php?p=183037&postcount=1

Tony
Click to expand...

Hi Tony,

I haven't been hanging around the RV forum too much, so you're right, I didn't see that post. Sounds like the only potential problem is with engine manufacturers continuous power specs. Fortunately, I'll be the engine manufacturer, so I don't anticipate any problems ;)

I also haven't read any of your build threads. When do you think you'll be flying?

Rusty
 
13brv3 said:
Hi Tony,

I haven't been hanging around the RV forum too much, so you're right, I didn't see that post. Sounds like the only potential problem is with engine manufacturers continuous power specs. Fortunately, I'll be the engine manufacturer, so I don't anticipate any problems ;)

I also haven't read any of your build threads. When do you think you'll be flying?

Rusty
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Rusty,

In the short rows. Should be ready for the first engine start tomorrow, then a few more days on the spinner, then a call to the FAA.

http://picasaweb.google.com/tonyboytoo/RV3BMiscellaneous/photo#5146917785795216914

Tony
 
Smaller engine?

Tony Spicer said:
Two years ago when I was starting my RV-3, I wondered if it would be possible for it to be LSA compliant. So I asked EAA. Their response from November 2005 follows:

----------------------------------------

"Since you are the builder of the aircraft you determine the gross weight, etc. and if operating as a sport pilot, you are responsible for flying only aircraft which qualify as an LSA.

...SNIP...

Practical considerations are that the burden of proof will be on you to establish that an RV-3 meets the definition. A knowledgeable FAA Inspector who "knows" that an RV-3 doesn't fit LSA will violate you first and then let you prove that it is in compliance. If the FAA has nothing else to go on, they will no doubt revert to the engine manufacturer's documentation, which will have a specific maximum continuous power rating (which definitely won't be 55% power!). For example, Lycoming calls out a maximum continuous rated power and RPM for the O-320-A2B of 150 hp and 2700 rpm. It would be pretty tough to convince an FAA inspector that the Lycoming engine in your homebuilt (even if it's modified in some way) has a substantially different maximum continuous power rating than what's on the TC. Van's probably will give you no support since they do not view it as LSA eligible.

Also, I would guess that you could also run into some insurance problems as they will use readily available reference material to determine what they will insure for sport pilot operations."

Tony Spicer (just the messenger)
Click to expand...


I don't know if you could climb-prop even a O-320 for less than 120 kts., but maybe a smaller engine - ie: O-235/O-290... something that would give you a excellent climb... and remain under the max LSA cruise? (plus you'd shave a couple more LSA sensitive pounds)

DJ
 
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0200 RV-3

Any body know What motor mount to use when using a 0200 on a RV-3,will a standard conical work or will you have to build a custom mount?
Bill
 
RV-3 / RV-4 LSA

Thought I'd take up the RV-3/4 LSA discussion...sure it can be done, to get a 'real' RV LSA (i.e., one with a tailwheel)

1. J-3 style cowl
2. No wheel pants or gear leg fairings
3. Round-head rivets on skin
4. Open cockpit for RV-3 or single-place -4

That should keep the top speed at around 135 with an 0-290 or 0-235. It should sound familiar, too...that was the configuration of the original T-18!

Now that I threw down the gauntlet I guess I gotta build one...

Any thoughts?
 
Stall Speeds

For the 4, build very light, and use VG's. It'll probably be a single-place airplane, though I would love to be proven wrong.
 
If I was going to make all those changes and still might not meet the stall speed, I would look for something that was designed for LSA from the start. Maybe a Fletcher CX4, I might be off on that name but it is close.
 
Wilddog, The name is Thatcher CX-4.. I am currently looking at building one until I can afford an RV-9.. Looks like a nice plane for the price..
 
AndrewBS said:
Still think it's possible - a -6 builder reported a 10-kt drop in stall speed (though there is possible intrument error)

Here' the link -

http://www.opensubscriber.com/message/[email protected]/2912150.html
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I don't doubt that his IAS at the stall might have decreased by that much. But it is extremely unlikely that the CAS at the stall decreased by anywhere close to that much, as that would require a huge increase in the maximum lift from the wing. Indicated airspeeds often have large errors at the stall, which probably explains how the IAS may have reduced that much.

It all depends on how the individual builder chooses to approach the LSA status. If you go at it honestly, it will be very difficult to get the stall speed low enough that you could put your hand on your heart and swear that you were certain the stall speed in CAS met the requirement.

But, if all you want to do is be able to say that "wink, wink, nudge, nudge, the stall speed is less than 45 kt", based on your IAS, then there is no problem. There are a number of different ways to introduce errors in the ASI so that you get impressively low IAS at the stall. But that would be a major misuse of the LSA privileges.
 
AndrewBS said:
...
That should keep the top speed at around 135 with an 0-290 or 0-235...
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You will want the O-235.

My O-290-D2 powered -9 w/ a climb prop is RPM limited to 140 Knots w/ or without the fairings. In other words, you will have to really restrict the RPM limit to keep it down to 120 Knots.
 
No argument there, that the CAS vs IAS question can be used to misuse the LSA privilege...and I would not suggest that to anyone. It's wrong, and would cast a bad light on us all. Sure, people do it.

My sole purpose in suggesting the possibility is to look at developing a good-flying platform that will give a traditional RV flavor. A single-seat, lightweight 4 with 'artificial drag' and some lift enhancement could very possibly meet the requirements cleanly. Looking at the numbers, a 3 probably would be harder.

Granted that there are a lot of other designs from which to choose. But 'narrow fuselage' RVs are special, and I believe that some development work to create a legitimate LSA may be worth while.

Or not..!
 
Doubt if you could get an insurance company to buy off on it but the question is. Why woud you want to dumb down an RV3 or 4 to a LSA?
Tom
 
As an aside, what about using the new O-340 engine from cubcrafters/ECI? 180hp on take off, but only rated for 80hp for max continuous power, which is what matters when determining max cruise for an LSA.
 
Is an LSA RV-3 possible?

I've often wondered if a smaller motor such as an A-65, C-75, C-85, etc. might be installed in an RV-3 airframe in such a way that the RV-3 would qualify as an LSA E-AB. The 51 mph stall is there and the gross is safely under 1320 lbs at 1100 lbs. The less powerful Continental motors weight nearly as much as the O-320. Is the only hurdle slowing the airplane down to 140 mph and possibly adding ballast to compensate for a lighter engine?

Extrapolating from the 55% cruise of 166 mph at 150 hp, it looks like 60-70 hp would give the required 140 mph using a climb prop. Would not the rate of climb at a similar weight and climb speed be a linear function of hp? Extrapolating from the published 1700 fpm rate at 150 hp, the 75 hp rate of climb would be 800-1000 fpm with a climb prop.

Could this be a path to an economical, aerobatic, high quality LSA?
 
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Not really from a practical standpoint. The maximum cruise speed at max continuous power is 120 kts/138 mph for LSA.
The stall speed must not be over 45 kts in the flaps up configuration. The 51 mph stall speed that Van lists is with full flaps.
 
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Mel said:
Not really from a practical standpoint. The maximum cruise speed at max continuous power is 120 kts/138 mph for LSA.
The stall speed must not be over 45 kts in the flaps up configuration. The 51 mph stall speed that Van lists is with full flaps.
Click to expand...

RV3 978TM with full flaps stalls at 48 mph ind at an estimated weight of 1150 lbs. Pretty sure you could make the 51 mph flaps up if you kept it real light. Can't imagine wanting to slow down a 200+mph airplane to meet LSA specs.
Don't get me started :eek:
Tom
 
Your rate of climb is not a linear function of HP. Subtract the power needed for level flight and use the excess power for climb. If it takes 50hp for level flight, then a 65hp plane would have 15hp for climb while the 150hp plane would have 100hp for climb, a big difference.
 
wilddog said:
Your rate of climb is not a linear function of HP. Subtract the power needed for level flight and use the excess power for climb. If it takes 50hp for level flight, then a 65hp plane would have 15hp for climb while the 150hp plane would have 100hp for climb, a big difference.
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Can you estimate the power an aircraft needs for level flight by looking at its service ceiling, then estimating percent power produced at that altitude and multiplying that by engine hp (assuming a normally aspirated engine)?
 
wilddog said:
Your rate of climb is not a linear function of HP. Subtract the power needed for level flight and use the excess power for climb. If it takes 50hp for level flight, then a 65hp plane would have 15hp for climb while the 150hp plane would have 100hp for climb, a big difference.
Click to expand...

FYI - One of the CubALikes LSA's uses a large engine and limits the max continuous climb power to a set time (or is it climb only?). That way you have a lot of HP for climb but must dial it back for cruise to stay under 120 knots. All "legal", right...
 
Correct this if needed please. The aircraft manufacture (builder in this case) Provides the aircraft, and paperwork for the experimental certification.

The builder provides limitations of the airframe/powerplant for approval. It's an experimental. The limitations are accepted, modified or added to by the FAA or DAR.

What about a builder limitation in the POH:

Max continuous power for this engine airframe combination is limited to XXXX RPM. Oh look there, the max speed with the installed prop, engine, and RPM limitation is...... below the LSA limit.

We have other prop RPM limits for C/S, FP Sen, etc..... Why not?

Perhaps your experimental prop (you as the builder determine suitability), you determine has a max RPM of 2100.....:cool:
 
So... how does Cubcrafters/ECI get away with their 180 hp LSA "Super Sport Cub? :eek: :confused:

http://cubcrafters.com/supersportcub/default.aspx

From their website:

CubCrafters newly certified engine is a modern upgrade of a well-proven design that has been in use around the world for over 50 years. The CC340 engine is certified to ASTM 2339 standards for Light Sport Aircraft. Working closely with ECI, the CC340 engine uses electronic ignition and high compression pistons to maximize power and economy. The engine weighs less than 250 Lbs, and is rated at 180 HP for take-off and climb, and 80 HP for continuous power settings. This allows for a 2,400 hour TBO, and fuel consumption of as little as 5 gallons per hour at cruise power settings.
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I think this is a pretty wild LSA... Too bad it is way out of my budget.

dj
 
Extrapolating rate of climb.

Yeah, the "linear function of hp ..." utterance was pretty lame. Amoung other things, I forgot the constant that keeps the resultant rate of climb positive. I guess the big question is what rate of climb one would get with the appropriate top-end limiting hp.
 
Estimating power for level flight

mcjon77 said:
Can you estimate the power an aircraft needs for level flight by looking at its service ceiling, then estimating percent power produced at that altitude and multiplying that by engine hp (assuming a normally aspirated engine)?
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(emphasis added)

You can do it easily and well with my methods as described in:
http://www.vansairforce.com/community/showthread.php?t=42703
You can do it with or without fuel flow instrument.

Your idea for using the service ceiling SC has some merit, but the SC is not the absolute ceiling. At SC, the airplane can still climb a little. At the absolute ceiling, you are about to stall. With most RV's that's oxygen territory. I'm not sure, either, that you could correctly compute the engine's actual power in such thin air. And, of course, since these are not certified aircraft, there is only one way to find out the SC or Absolute ceiling and that's to try it. I guess if you got down to 100' per minute you could to the numbers from that if you knew the weight...
http://en.wikipedia.org/wiki/Ceiling_(aeronautics)
 
I still think the RV-3 is very close to being the ultimate single-seat LSA - professionally engineered, proven, aerobatic, economical, and extremely sexy. The stall speed issue is certainly solvable. There are huge benefits to "taking a 200 mph airplane and slowing it down."

The LSA movement is sometimes unfairly characterized as a bunch of washed-up pilots who lost their medicals. In my opinion it is much, much more. It essentially grants sweeping freedoms enabling pilots, builders, and manufacturers to self-certify their activities. I'm one of a growing number of pilots who are making the LSA choice, not because they have to, but because they want to.

Let's stop whining and light this candle!
 
WilliamRich said:
I still think the RV-3 is very close to being the ultimate single-seat LSA - professionally engineered, proven, aerobatic, economical, and extremely sexy. The stall speed issue is certainly solvable. There are huge benefits to "taking a 200 mph airplane and slowing it down."
Click to expand...

Increase the wingspan to 23'. Install a AeroVee 80 hp engine.

Wing loading will be about the same as an RV 12.
Power to weight will be about the same as an RV 12.
Top speed would need to be controlled with the prop.
 
How about leading edge slats?

How about keeping the same wing and a 150hp motor, but add some
full span fixed leading edge slats, and use a climb pitched prop. I bet
the slats might lower the flaps-up stalling speed enough to qualify, and
a climb prop, combined with the extra drag of the slats at cruise might
lower the cruising speed enough to qualify. Plus, it would probably climb
like a bat out of ****, as if it doesn't already, and take off and land
even shorter than it does now. Maybe some tundra tires would be
in order to further lower the cruising speed if needed.

RV-3a
N1131T
 
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I'm giving serious though to attempting an LSA RV-3. My biggest concern (duh) is getting LSA approval for the craft. I'm a new builder, could someone here counsel me on how best to determine if my project will be approved with a minimum risk of time and money (assuming a reasonable concept addressing the stall speed can be proffered).

Also, being a lazy keyboard worker (systems analyst) I'm naturally inclined to codify much of the RV-3 cutting and drilling using Solid Works and then have the pieces cut for me. Has anyone here done that and are you willing to share your files, or has prudent forethought deemed such a program wasteful? I suspect there are plenty of cutting tables sitting idle in the LA basin. There must be boundaries to such notions with respect to Van and his wishes - I'm all ears ( I'm kind of the P.T.Barnum of half-baked ideas).

Traditional wisdom says the biggest hinderance to the concept is that it is not cost effective with respect to two-seat alternatives. The partial remedy is to make sure the single-seater is aerobatic - presumably ones loneliness is salved with Gs.

Then again, the talk of an LSA RV-4 is a whole new ball game ...
 
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